The present invention relates to a knife and sheath assembly, and is particularly concerned with such assemblies for use underwater by divers.
Various types of knives such as sporting or utility knives are typically stored with their cutting blade within a suitable protective sheath when not in use. In some cases, the knife is held in the sheath by frictional engagement between the blade and sheath. However, such an arrangement is not suitable for underwater use, because the blade may accidentally slide out of the sheath when the diver is swimming through the water, or as the diver initially jumps into the water. Divers therefore need to have a knife and sheath arrangement in which the knife is securely held in the sheath while the diver is moving through the water, yet can be readily removed by the diver as needed.
Some prior art diver""s knives incorporate mechanical locking devices to hold the knife in the sheath, and the sheath is suitably secured to the diver""s belt or waistband. This type of assembly is described, for example, in U.S. Pat. Nos. 4,404,747, 5,067,239 and 5,379,520 of Collins.
It is an object of the present invention to provide a new and improved knife and sheath assembly which is particularly suitable for use by divers.
According to the present invention, a knife and sheath assembly is provided, which comprises a knife having a handle and a blade, and a sheath having a cavity for releasably receiving the blade of the knife in a storage condition, and at least one attachment device for securing the sheath to a diver, diving equipment or clothing. The knife blade has a first end portion adjustably mounted in the handle and a second end portion having a cutting edge protruding from the handle, the first end portion being movable between a first, retracted position in which a first length of the blade protrudes from the handle and a second, extended position in which a second length of the knife blade longer than the first length protrudes from the handle. The handle has a releasable latch member for releasably locking the knife blade in each of the two positions. The sheath cavity is designed for receiving the knife blade in the retracted position, such that the overall length of the assembly when in the storage condition can be reduced, and the knife blade can be readily extended when removed from the sheath for use.
In an exemplary embodiment, the same latch member is used both to secure the knife blade in the retracted position and to secure the knife in the sheath, so that a single latch release action can be used both to remove the knife from the sheath and to extend the blade into its fully extended position. A suitable biasing device such as a spring within the handle biases the knife blade from the retracted to the extended position. A non-metallic member may be positioned between an inner end of the knife blade and the spring in order to electrically insulate the metallic components from one another in order to inhibit galvanic corrosion.
The knife and sheath assembly may be selectively mountable on various different items of diver""s clothing or equipment, or about the diver""s forearm. The sheath in an exemplary embodiment has a through slot for receiving a belt or strap which is secured about the diver""s waist, forearm, or leg, if desired, and also has threaded holes for receiving bolts or the like for securing the sheath to a bc (buoyancy compensator) or hose clamp.
In an exemplary embodiment, the knife blade has opposite side edges, and a pair of spaced notches are provided in one side edge for releasable engagement with the latch member in the retracted and extended positions. The latch member in this case has a latching edge or tang which is resiliently biased into the respective notch when the blade is moved into the extended or retracted position, and a manually engageable portion of the latch member can be pushed by the user in order to release the tang from the respective notch. The outermost notch may also have a cutting edge for providing a line cutter when the blade is extended.
The knife and sheath assembly of this invention therefore will be more compact than conventional diver""s knives when the blade is stored in the sheath in the retracted position. This will make it less obtrusive to the diver when the knife is not in use. It can also be secured in any one of a number of convenient locations about the diver, the diver""s clothing, or the diver""s equipment.